In data acquisition, a voltage/frequency converter can often replace an analog/digital or digital/analog converter. A voltage/frequency converter emits as an output a frequency signal which is proportional to the input voltage instead of a binary parallel code word. The analog part of a circuit can be easily isolated from the digital part. Therefore, voltage/frequency converters are used in various areas of electrical and electronic engineering. For example, when controlling electric motors, the actual current or voltage values can be easily integrated into a digital control system by converting the actual current or voltage values into a proportional sequence of pulses.
For integrating the detection of the actual voltage or current value into a digital control system, it is desirable to convert the continuous signal at the location of its detection into a proportional frequency signal and to transmit it in the form of pulses with a variable pulse repetition frequency. In this manner, a high interference immunity is guaranteed, since only small demands are made on the pulse shape in further processing of the pulses.
An economical, and therefore, a very quick and highly accurate digitization of a continuous input signal having great frequency deviation cannot be realized solely by conventional voltage/frequency converters. Thus, there is a need for a method and a device which realizes a quick, highly accurate voltage/frequency conversion having a large frequency deviation using simple means.